gson

Java gson, ClassCastException on decoding to Map<String,String[]>

由 别来无恙 提交于 2021-01-04 09:15:23
问题 I want to decode a json string like {"username":["emmet"]} to a Map<String,String[]> object. using following code: String json = "{\"username\":[\"emmet\"]}"; Gson gson = new GsonBuilder().create(); Map<String,String[]> map = new HashMap<>(); map = (Map<String,String[]>)gson.fromJson(json, map.getClass()); String[] val = map.get("username"); System.out.println(val); this exception occurs: Exception in thread "main" java.lang.ClassCastException: java.util.ArrayList cannot be cast to [Ljava

What is the equlent libary avalable in flutter dart like Gson in java

由 ⅰ亾dé卋堺 提交于 2021-01-02 06:04:14
问题 Is there any library available to save object and restore it. In android java we using Gson to do this but in flutter there is no Gson 回答1: A library like GSON won't be possible in Flutter, since Flutter doesn't support code reflection. Reflection interferes with tree shaking which flutter needs to clean out unused code and give a compact app. more on the topic and alternatives here You can use this site to convert your JSONs to class and it prepares the toJson fromJson methods automatically.

老大爷都能看懂的RecyclerView动画原理

由 孤人 提交于 2020-12-30 21:05:55
如何阅读本篇文章 本文主要讲解RecyclerView Layout变化触发动画执行的原理。前半部分偏重原理和代码的讲解，后半部分通过图文结合场景讲解各个阶段的执行过程。 建议先粗略阅读前半部分的原理和代码篇，做到心中有概念，带着理论知识去阅读后半部分的场景篇。最后结合全文学到的知识，带着问题去阅读源码，效果会更好。 原理篇 1. Adapter的notify方法 用过RecyclerView的同学大概都应该知道Adapter有几个notify相关的方法，它们分别是： notifyDataSetChanged() notifyItemChanged(int) notifyItemInserted(int) notifyItemRemoved(int) notifyItemRangeChanged(int, int) notifyItemRangeInserted(int, int) notifyItemRangeRemoved(int, int) notifyItemMoved(int, int) 稍微有点开发经验的同学都知道，notifyDataSetChanged()方法比其它的几个方法更重量级一点，它会导致整个列表刷新，其它几个方法则不会。有更多开发经验的同学可能还知道notifyDataSetChanged()方法不会触发RecyclerView的动画机制

SpringBoot整合WEB开发--（一）处理JSON返回数据

由 Deadly 提交于 2020-12-29 00:42:13
1.使用默认的json转换HttpessageConverter Json是目前主流的前后端数据传输方式，SpringMVC中使用消息转化器HttpMessageConverter对JSON的转换提供了很好的支持，在SpringBoot中对相关配置做了进一步简化。 pom.xml <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> 这个依赖中默认加入了jacjson-databind作为JSON处理器，此时不需要添加额外的Json处理器就可以返回json了。 public class Book { private String name; private String author; @JsonIgnore // 过滤掉这个属性 protected Float price; @JsonFormat(pattern = "yyyy-MM-dd") // 格式化输出这个属性 private Date publicationDate; // 省略getter/setter } @RestController public class BookController { @GetMapping( "

Custom PrintFormatting for GSON

由 这一生的挚爱 提交于 2020-12-27 05:55:36
问题 I'm having some trouble with GSON in regards to printing. GSON has two options when it comes to printing. Pretty Printing Compact Printing I intend to use a modified form of Pretty Printing and even though the documentation says JsonPrintFormatter is the class which is used to modify the output format. I can't find that class in the GSON repository! Any ideas on why this is the case or anyway I can modify the GSON printing? Apart from that, any libraries used to modify spacing or formatting

【实战问题】【15】报错java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast t...

由 ≡放荡痞女 提交于 2020-12-20 07:11:08
场景重现： 调用封装好的接口，返回的数据类型是List，debug可以看到有返回值。但是进行到对list进行操作的那步，报错了（java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to xx）。原来list中的数据是LinkedTreeMap 格式的，并没有转换成对应的实体类。网上查的方法很多是解决json格式字符串转成实体类，而我因为接收到的就是List数据，所以还是想转成能使用的List数据。 写在前面： 尝试多种方法没有解决问题，最终是改了封装的接口，数据格式从源头就错了 原因： 泛型<T>不能强转为List，会有一系列问题 排查历程： （1）最开始我的代码 获取到了List，取出状态有效的数据。如此简单，开心。 // 主要代码 List<UserEntity> userList = this .commentService.getUserList(userId); // 获取数据的接口 List<UserEntity> newList = list.stream().filter(i -> i.getStatus() == 1).collect(Collectors.toList()); // 报错 然后就报错了，返回的数据格式是这样的： （2

org.openqa.selenium.remote.UnreachableBrowserException: Error communicating with the remote browser. It may have died with ChromeDriver and Selenium

由 ↘锁芯ラ 提交于 2020-12-12 10:49:08
问题 I'm running a bunch of test cases every hour using selenium-java 3.12.0; TestNG; Selenoid with docker, Jenkins. Sometimes (about 1 out of 10 cases) I get the error: org.openqa.selenium.remote.UnreachableBrowserException: Error communicating with the remote browser. It may have died. Build info: version: '3.6.0', revision: '6fbf3ec767', time: '2017-09-27T15:28:36.4Z' System info: host: 'autotest.rvkernel.com', ip: '94.130.165.217', os.name: 'Linux', os.arch: 'amd64', os.version: '4.13.0-26

期末作业、课程设计的最优选择:Android商城开源项目

由 只愿长相守 提交于 2020-12-11 00:12:13
项目说明: 1.完整功能的项目. 2.代码采用基础型代码,比较适合在校大学生风格,没有晦涩、难懂的编程风格. 3. 有数据库. 项目简介: 购物(商城)类app,项目主要分为主页、热卖、分类、购物车、我的五大板块. 该app基本上覆盖市面上商机级商城类app的功能,包括购物车、微信及支付宝支付、热门及历史搜索、登录注册、收货地址管理等. 另外,本项目持续维护中!!!同时可进入微信群,和作者、其他小伙伴一起谈论该项目. 截止目前项目提交记录: 对应的群进行交流学习: 使用的开源技术(蓝色字体含链接): 1. 轮播图 2. 下拉刷新、加载更多 3.Gson解析 4. butterknife 5. 批量处理权限 6. 自定义样式的dialog 7. 三级联动 8. eventBus 9. 沉浸式状态栏 10. greendao 11.ShareSDK 12. okhttpUtils 13. baseAdapter 14. Glide 15. pingpp 16.百度地图定位及Mob天气查询 基本封装与自定义: 1.ToolBar的封装 2.FragmentTabHost的自定义 3.一键清除的EditText 4.购物车的加减控件 5.短信验证倒计时的定时器 6.Glide的封装 7.购物车本地缓存 8.对称加密DESUtil 9.读取Json文件的工具类GetJsonDataUtil

Exclude a Kotlin data class property/field from serialization/deserialization using gson

由 拥有回忆 提交于 2020-12-10 02:37:20
问题 I am trying to exclude a Kotlin property from deserialization using gson. I have tried different methods from annotating the property with @Transient to creating a custom annotation strategy (specifying the strategy in the gson builder of course), but nothing seems to be working, as the property keeps getting null instead of the value I initialized the property with. I have not tried using the @Expose annotation, but I do not want to annotate other fields with @Expose Please, how can I

Exclude a Kotlin data class property/field from serialization/deserialization using gson

由 末鹿安然 提交于 2020-12-10 02:35:06
问题 I am trying to exclude a Kotlin property from deserialization using gson. I have tried different methods from annotating the property with @Transient to creating a custom annotation strategy (specifying the strategy in the gson builder of course), but nothing seems to be working, as the property keeps getting null instead of the value I initialized the property with. I have not tried using the @Expose annotation, but I do not want to annotate other fields with @Expose Please, how can I
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